晶场二级效应与交换作用对PrF_3晶体磁性及磁光性质的影响

Effect of the secondary crystal field-effect and the exchange interaction on magnetic and magneto-optic properties of PrF_3

研究了晶场二级效应在PrF3晶体中的作用,发现该效应可使Pr3+离子的晶场单态与其他态混合,对PrF3晶体磁化率产生明显影响.进一步研究了晶体内的交换作用有效场,其形式为Hin=(1.9-0.02556T)×10-5M,在100—300K的温度范围内,以此计算的PrF3晶体的倒数磁化率和Verdet常数的倒数与实验值符合较好.结果表明,在PrF3晶体中,晶场二级效应与离子间的交换作用都不能忽略.

In the PrF3 crystal, the lowest crystal field state of Pr^3＋ ion is a single state, which has no contribution to the susceptibility and the Verdet constant of the crystal in first-order effect. The secondary crystal field-effect admixes the state with other states and makes the state have a great contribution to the magnetic properties of PrF3 crystal. In this paper, the effect of secondary crystal field-effect on the magnetic and magnetio-optic properties of PrF3 crystal is presented. Furthermore, the effective field of exchange interaction between the ions is investigated, which has the form is Hin = （1.9- 0.02556 T） × 10^-5M. By means of the effective field, the inverses of the magnetic susceptibility and Verdet constant of PrF3 crystal as functions of temperature are calculated, and the results are in good agreement with the measured ones. The results show that the crystal field＇s second-order contribution and exchange interaction between ions shouldn＇t be ignored.